Influence of the chain and layer structure of Fe(III) and In(III) aqua-pentachloro-complexes on the bending vibrations of water molecules

Studies of IR and Raman spectra of monohydrates M^I₂[M^IIICl₅(H₂O)] (where M^I=K⁺, Rb⁺, Cs⁺ and M^III=Fe³⁺, In³⁺) at 1400-1900 cm⁻¹ have been carried out. The medium intensity band, detected in the region 1580-1595 cm⁻¹ was assigned to bending vibrations of water molecules (δHOH). The shift of the δHOH band towards low wavenumbers (1580-1595 cm⁻¹) is a main sign of the water molecule interactions in the chain hydrates. Additionally in the IR and Raman spectra of these salts, the appearance of the low intensity band between 1750 and 1810 cm⁻¹ (ν_x(H₂O)) was observed. In the presented paper we also discuss the influence of M^I and M^III cations on the position and splitting of these bands.     

A new binuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid: Crystal and molecular structure of [(H2O)(OH)Ge(μ-Hpdta)Cu(H2O)] · 3H2O

A heteronuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid (H₅Hpdta) has been synthesized for the first time. The compound has been characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. The structure of the complex [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] · 3H₂O (I) has been determined by single-crystal X-ray diffraction. The crystals of I are monoclinic, a = 1 5.327(4) Å, b = 11.626(3) Å, c =21.058(3) Å, β = 96.35(2)°, V = 3729.2(2) ų, Z = 8, space group C2/c, R1 = 0.0551 on 3090 reflections with I > 2σ(I). The structural units of the crystal of I are binuclear complex molecules [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] and crystal water molecules. The germanium and copper atoms are linked by the bridging oxygen atom of the deprotonated isopropanol group of the Hpdta^5? ligand (Ge-O, 1.843(3) Å; Cu-O, 2.221(3) Å). The coordination spheres of the Ge and Cu atoms contain each one nitrogen atom (Ge-N, 2.090(4) Å; Cu-N, 2.000(4) Å) and two carboxyl oxygen atoms from four acetate arms of the heptadentate Hpdta^5? ligand (av. Ge-O, 1.909(3) Å; Cu-O, 1.948(3) Å). The coordination polyhedron of the Ge atom is completed to a distorted octahedron by the oxygen atoms of the terminal hydroxy group (Ge-O, 1.786(3) Å) and a water molecule (Ge-O, 1.904(3)Å). The coordination polyhedron of the copper atom is completed to a prolate tetragonal pyramid (4 + 1) by the oxygen atom of a water molecule in the equatorial position (Cu-O, 1.955(4) Å) and the bridging O(11) atom (Hpdta^5?) in the apical position. Binuclear molecules are linked pairwise in a head-to-head manner via double Cu-O(2) bridges to form the centrosymmetric tetranuclear supramolecule {[(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)]}₂. The coordination of the Cu atom is completed by the weak Cu-O(2A) contact (3.303 Å) to an asymmetrically elongated tetragonal bipyramid (4 + 1 +1). In the crystal, the complex molecules and crystal water molecules are combined by a system of hydrogen bonds into a three-dimensional framework.     

Synthesis and structural determination of a novel complex [Yb<Superscript>III</Superscript>(HEgta)] · 4H<Subscript>2</Subscript>O in comparison with [Yb<Superscript>III</Superscript>(HEgta)] · 2H<Subscript>2</Subscript>O

One novel ytterbium complex [Yb^III(HEgta)] · 4H₂O (I), where H₄Egta = ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, has successfully been synthesized by the reaction of Yb₂O₃ with H₄Egta in an aqueous solution after refluxing for 18 h. The crystal and molecular structures were determined by the infrared spectrum and X-ray crystallography. The crystal structural analysis reveals that central Yb(III) in I is eight-coordinated in a geometry of pseudo-square antiprismatic polyhedron by two amine N atoms, two ethylene glycol O atoms, and four carboxyl O atoms from one HEgta ligand and crystallizes in the orthorhombic crystal system with P2₁2₁2₁ space group. The crystal data are as follows: a = 9.4927(8), b = 12.2627(13), c = 18.3657(17) Å, V=2137.9(4) ų, Z = 4, ρ_calcd = 1.934 mg/m³, μ = 4.448 mm^?1, F(000) = 1236, R = 0.0291, and wR = 0.0714 for 8850 observed reflections with I ≥ 2σ(I). In addition, there is a protonated coordinated carboxyl O atom (O(5)) in the [Yb^III(HEgta)] moiety.     

A restudy of the crystal structure of tetraaquastrontium dicitratoborate trihydrate

The crystal structure of Sr(H₂O)₄[(C₁₂H₁₁O₁₄)B] · 3H₂O (I) has been restudied and determined with a higher accuracy. The crystals are monoclinic, space group P2₁/n, a = 11.405(1) Å, b = 18.814(1) Å, c = 11.987(1) Å, β = 110.79(1)°; Z = 4. The structure was refined by full matrix least-squares calculation to R = 0.0547 on 5343 unique reflections with R _int = 0.0419. The structural units of crystal I are the Sr²⁺ cation, seven water molecules, and doubly charged dicitratoborate anion, which is not equivalent to the singly charged complex dicitratoborate anion identified previously in the crystal structures of complexes of boric and citric acids. The coordination polyhedron of the Sr²⁺ cation is a distorted dodecahedron composed of four O atoms of coordinated water molecules and four O atoms of two complex anions. The crystal packing of I is layered. Thirteen independent O-H…O and O-H…, O′ contacts form an intricate system of hydrogen bonds.     

Ion-selective properties of 1,8-bis [2-(dihydroxyphosphinyl)phenoxy]-3,6-dioxaoctane (H4L3), synthesis and vibrational spectra of copper and zinc complexes with H4L3, and crystal and molecular structure of [Cu(H4L3)(H2O)3][(H2L3)(H2O)]

The ion-selective properties of 1,8-bis[2-(dihydroxyphosphinyl)phenoxy]-3,6-dioxaoctane (H₄L³) have been studied and its potentiometric selectivity coefficients have been determined. New complexes [Cu(H₄L³)(H₂O)₃][(H₂L³)(H₂O)] (I) and Zn(H₄L³)(H₂L³) · 3H₂O, and Cu(H₂L³) · 2(H₂O) have been synthesized and characterized. The crystal and molecular structure of I has been determined by X-ray crystallography and vibrational spectroscopy. The crystals are monoclinic, a = 10.279(5) Å, b = 26.532(13) Å, c = 8.399(4) Å, β = 99.270(8)°, V = 2260.8(7) ų, Z = 2, space group Cm, R = 0.0347 for 4325 reflections with I > 2σ(I). Ionic compound I is composed of the [Cu(H₄L³)(H₂O)₃]²⁺ complex cations and [(H₂L³)(H₂O)]^2? anions. In the cation, the Cu²⁺ cation located in the m plane is bound to a tetragonal pyramidal (TP) array. The equatorial plane of the TP is formed by two phosphoryl oxygen atoms of the podand (Cu(1)-O, 1.921(2) Å) and two O atoms of two water molecules (av. Cu(1)-O, 1.981(3) Å). The third water molecule is at the axial vertex of the TP at a considerably larger distance (Cu(1)-O, 2.139(3) Å). The anion is of the host-guest type. The host is the deprotonated podand (H₂L³)^2?, and the guest is the water molecule. The latter is bound to the terminal hydroxyl groups of two phosphoryl groups of the podand by two acceptor hydrogen bonds and to two central ether oxygen atoms of the (H₂L³)^2? anion by one donor bifurcated hydrogen bond. The cations and anions in the structure are linked by hydrogen bonds to form chains parallel to the c axis.     

Synthesis, vibrational spectra, and crystal and molecular structure of copper 1,5-bis[2-(dihydroxyphosphinyl)phenoxy]-3-oxapentane dihydrate [Cu(H2L2)(H2O)2]

A new complex Cu(H₂L²)(H₂O)₂] (I), where H₄L² is 1,5-bis[2-(dihydroxyphosphinyl)phenoxy]-3-oxapentane, has been synthesized and characterized. Its molecular and crystal structure has been determined by X-ray crystallography and vibrational spectroscopy. In mononuclear complex I, the copper(II) cation is in a distorted square-planar environment of two water oxygen atoms and two oxygen atoms of the chelating dianion (H₂L²)^2?. The crystals are orthorhombic, space group Cmc2₁, a = 25.909(5) ?, b = 9.1500(18) ?, c = 8.5600(17) ?, V = 2029.3(7) ?³, Z = 4, ??_calc = 1.688 g cm^?3, ?? = 1.292 cm^?1; 3107 measured reflections, 1174 reflections with I > 2.0??(I), R _int = 0.0600, GOOF = 1.413, R ₁ (I > 2??(I)) = 0.0812, wR ₂ (I > 2??(I)) = 0.2145.     

Characterisation by rotational spectroscopy of a hydrogen-bonded dimer formed between H2O and HCN

The rotational spectra in the vibrational ground states of (H₂O, HC¹⁴N) and (H₂O, HC¹⁵N) have been assigned in the frequency range 6–19 GHz. Values of rotational constants (B_O, C_O) and centrifugal distortion constants (Δ_J, Δ_JK) have been determined for both species, while the ¹⁴N-nuclear quadrupole coupling constants x_aa and x_bb have been established for the first. Observations concerning additional hyperfine structure arising from H,H nuclear spin-nuclear spin coupling in the H₂O subunit suggest that (H₂O,HCN) has a pair of equivalent protons and is effectively planar in the zero-point state. Observed spectroscopic constants are consistent only with the arrangement H₂O…HCN, with r(O…C) = 3.1387 Å.     

Synthesis and characterization of heteronuclear germanium(IV) and lanthanum(III) (chromium(III)) complexes with 1,3-diamino-2-propanoltetraacetic acid: Crystal and molecular structure of [Ge(OH)(μ-Hpdta)(μ-OH)La(H2O)4] · H2O

Two heteronuclear germanium(IV) and lanthanum(III) (chromium(III)) complexes with 1,3-diamino-2-propanoltetraacetic acid (H₅Hpdta) have been synthesized. The compounds have been characterized by elemental analysis and X-ray powder diffraction data. The structure of [Ge(OH)(??-Hpdta)(??-OH)La(H₂O)₄] · H₂O (I) has been determined by X-ray crystallography. The crystals are monoclinic, a = 9.3805(3) ?, b = 10.3023(4) ?, c = 21.6527(6) ?, ?? = 94.829(2)°, V = 2085.10(12) ?³, Z = 4, space group P2₁/n, R1 = 0.0294 based on 5480 reflections with I > 2??(I). Compound I is composed of binuclear [Ge(OH)(??-Hpdta)(??-OH)La(H₂O)₄] molecules and crystal water molecules. In the dimeric molecule, the germanium and lanthanum atoms are linked by the bridging oxygen atom of the hydroxo ligand and the oxygen atom of the deprotonated isopropanol group of Hpdta^5?. The coordination spheres of germanium and lanthanum each contains one nitrogen atom and two carboxyl oxygen atoms of the four acetate arms of the heptadentate Hpdta^5? ligand. The Ge coordination polyhedron is completed to a distorted octahedron by the oxygen atom of the terminal hydroxo group, and the lanthanum coordination polyhedron is completed to a nine-vertex polyhedron by the oxygen atoms of four water molecules. In crystal, the complex molecules and crystal water molecules are combined by a system of hydrogen bonds.     

Molecular Zeeman effect of 3-oxetanone and 3-methylene oxetane,and the comparison of the magnetic-susceptibility anisotropies,molecular quadrupole moments,and other magnetic parameters with other four-membered rings

The molecular Zeeman effect is reported for 3-oxetanone and 3-methylene oxetane at fields near 20000 G. The results for 3-oxetanone are molecular g-values: g_aa = ?0.1059 ± 0.0008, g_bb = ?0.0581 ± 0.0004,g_cc = ?0.0437 ± 0.0004, magnetic susceptibility anisotropies:2x_aa -x_bb - x_cc = (9.6±0.5) x 10^?6 erg/G²mole, 2x_bb - x_aa - x_cc = ?(7.8±0.6) x 10^?6 erg/G²mole, and molecular quadrupole moments: Q_aa = ?(12.8±0.8) x 10^?26 esu cm,Q_bb = (7.9±0.8) x 10^?26 esu cm, and Q_cc = (4.9±0.8) x 10^?26 esu cm. For 3-methylene oxetane, the results are g_aa = ?0.0510 ± 0.0018, g_bb = ?0.0435 ± 0.0010, g_cc = ?0.0313 ± 0.0010, 2x_aa - x_bb - x_cc = ?(10.9±0.5) x 10^?6 erg/G² mole, 2x_bb - x_aa - x_cc = (2.3±0.9) x 10^?6 erg/G² mole, Q_aa = -?5.4±1.0) x 10^?26 esu cm, Q_bb = (5.1 ± 1.2) x 10^?26 esu cm, and Q_cc = (0.2±1.5) x 10^?26 esu cm. The bulk magnetic susceptibility for 3-oxetanone was measured to be x = 1/2 (x_aa+x_bb+x_cc) = ?(30.6±1.5) x 10^?6 erg/G² mole. The out-of-plane minus average in-plane magnetic-susceptibility anisotropies in four-membered rings show larger paramagnetism than predicted on the basis of localized group susceptibility anisotropies. This effect is discussed and a possible explanation presented.     

Syntheses and structures of mononuclear eight-coordinate Na[ErIII(Cydta)(H2O2]·5H2O (Cydta = trans-1,2-cyclohexanediaminetetraacetic acid) and binuclear nine-coordinate Na2[SmIII(Cydta)][SmIII(Cydta)(H2O)3] · 11H2O

The title complexes, Na[Er^III(Cydta)(H₂O)₂] · 5H₂O (I) and Na₂[Sm^III(Cydta)][Sm^III(Cydta)(H₂O)₃] · 11H₂O (II) (Cydta is trans-1,2-cyclohexanediaminetetraacetic acid), are prepared and characterized using IR, elemental analyses, and single-crystal X-ray diffraction techniques. Crystal I belongs to triclinic system (space group P1), which has a mononuclear eight-coordinate slightly distorted square antiprismatic conformation. The crystal data are as follows: a = 8.371(12) Å, b = 9.952(14) Å, c = 14.74(2) Å, α = 88.32(2)°, β = 76.30(2)°, γ = 87.87(2)°, V = 1192(3) ų, Z = 1, ρ = 1.835 g/cm³, μ = 3.612 mm^?1, F(000) = 658, R = 0.0194, and wR = 0.0520 for 4130 observed reflections with I≥2σ(I). Crystal II belongs to monoclinic system (space group P2₁/n), which has the binuclear nine-coordinate structure with tricapped trigonal prismatic conformation for Sm(1) and the pseudomonocapped square antiprismatic conformation for Sm(2). The crystal data are as follows: a = 12.283(6) Å, b = 15.626(7) Å, c = 25.875(12) Å, β = 97.962(7)°, V = 4919(4) ų, Z = 4, ρ = 1.717 g/cm³, μ = 2.476 mm^?1, F(000) = 2536, R = 0.0781, and wR = 0.1745 for 8554 observed reflections with I ≥ 2σ(I).     

Syntheses and structures of seven-coordinate K3[Cd(Dtpa)], K2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O, and Na2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O complexes

The title complexes, K₃[Cd(Dtpa)] (H₅Dtpa = diethylenetriamine-N,N,N,N′,N′-pentaacetic acid, (I)), K₂[Cd(H₂O)₄][Cd(Edta)(H₂O)]₂ · 2H₂O (H₄Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid, (II)), and Na₂[Cd(H₂O)₄][Cd(Edta)(H₂O)]₂ · 2H₂O (III), were prepared, and their compositions and structures were determined by elemental analyses, IR spectra, and single-crystal X-ray diffraction techniques, respectively. In complex I, the Cd is seven-coordinated by one Dtpa ligand yielding a pseudo-monocapped trigonal prism conformation, and the complex crystallizes in the triclinic crystal system with the Pi space group. The crystal data are as follows: a = 8.7300(17), b = 9.1200(18), c = 15.110(3) Å, α = 95.52(3)°, β = 96.59(3)°, γ = 99.63(3)°, V = 1170.0(4) ų, Z = 2, ρ = 1.754 g/cm³, μ = 1.519 mm^?1, F(000) = 616, R = 0.0644 and wR = 0.1712 for 3842 observed reflections with I ≥ 2σ(I). For complex II, in the [Cd(Edta)(H₂O)]^2? complex anion the Cd²⁺ ion is seven-coordinated by one Edta ligand and one water molecule, yielding a pseudo-pentagonal bipyramid conformation. In the [Cd(H₂O)₄]²⁺ cation, the bridged Cd is six-coordinated, yielding an almost standard octahedral conformation. The complex crystallizes in the monoclinic system with P2₁/n space group. The crystal data are as follows: a = 9.098(3), b = 16.442(6), c = 12.023(4) Å, β = 91.053(6)°, V = 1798.3(12) ų, Z = 2, ρ = 2.098 g/cm³, μ = 2.086 mm^?1, F(000) =1124, R = 0.0406 and wR = 0.1152 for 3680 observed reflections with I ≥ 2σ(I). In complex III, the conformations of Cd²⁺ ions are similar to those of the potassium salt complex, and the complex also crystallizes in the monoclinic crystal system with the P2₁/n space group. The crystal data are as follows: a = 9.134(7), b = 16.500(13), c = 12.075(10) Å, β = 91.054(12)°, V = 1820(2) ų, Z = 2, ρ = 2.015 g/cm³, μ = 1.856 mm^?1, F(000) = 1092, R = 0.0363 and wR = 0.0879 for 3707 observed reflections with I ≥ 2σ(I).     

Nickel(II) tetraaqua bis(benzoate) tris(phenylacethydrazide) complex [Ni(HL<Superscript>1</Superscript>)<Subscript>3</Subscript>](L<Superscript>2</Superscript>)<Subscript>2</Subscript> · 4H<Subscript>2</Subscript>O: Synthesis and crystal and molecular structure

The synthesis, IR and Raman spectroscopic study, and X-ray diffraction analysis of [Ni(HL¹)₃](L²)₂ · 4H₂O (I), where HL¹ is phenylacetic acid hydrazide and L² is the benzoate monoanion, have been performed. The structural units of a crystal of complex I are complex [Ni(HL¹)₃]²⁺ cations, (L²)^– anions, and crystallization water molecules. The nickel atom is coordinated to the three oxygen atoms at octahedron apices and the three nitrogen atoms of three bidentate chelate (О, N) ligands HL¹ in cis,trans-meredianal (fac) conformation. The structural units of a crystal of complex I are bonded by a branched network of О–Н···О and N–H···O hydrogen bonds.     

Synthesis and crystal structure of octaaquaerbium(III) 4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane pentabromide hydrate

A new complex salt [Er(H₂O)₈]³⁺·[H₂(Crypt-222)]²⁺·5Br^?·1.5H₂O(I) is synthesized, and its crystal structure is studied by single-crystal X-ray diffraction analysis (space group P2₁, a = 8.315 Å, b = 32.000 Å, c = 8.383 Å, β = 120.03°, Z = 2; direct method, anisotropic full-matrix least-squares approximation, R = 0.050 for 3755 independent reflections; CAD4 automated diffractometer, λMoK _α radiation). The structural units of crystal I are complex cations [Er(H₂O)₈]³⁺, disordered dications of the 2.2.2-cryptand (with two protonated nitrogen atoms), Br^? anions, and water molecules. The coordination polyhedron of the Er³⁺ cation is a tetragonal antiprism with the oxygen atoms of eight water molecules at its vertices. The disordered [H₂(Crypt-222)]²⁺ dication contains trifurcate hydrogen bonds N⁺-H(?O)₃.     

IR- und Raman-Spektren einiger Kaliumpentafluorometallate-monohydrate

The IR- and Raman Spectra of several compounds of the stoichiometryM ₂ ^I M ^IIIF₅H₂O and their deuterated analogs have been interpreted on the basis of their crystal structures. The compounds studied were divided into two classes regarding the bonding of water molecules. The main spectroscopic difference between the two classes was found in the region of H₂O vibrations in good agreement with theoretical predictions. The metal—fluorine and metal—oxygene vibrations gave no direct information concerning the two types of water.     

Synthesis and crystal structure of KBi(C6H4O7) · 3.5H2O

A novel compound, KBi(C₆H₄O₇) · 3.5H₂O (I), has been synthesized in the Bi(NO₃)₂-K₃(HCit) system (HCit^3? is an anion of citric acid C₆H₈O₇) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 ų, Z = 2, space group $P\bar 1$ . In the structure of I, asymmetric binuclear fragments [Bi₂(Cit^4?)₂(H₂O)₂]^2? are linked through inversion centers into polymeric chain anions. Ions K⁺ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi₂O₂ formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.     

Synthesis and crystal structure of [Na(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>][EuL<Subscript>4</Subscript>] · 0.775CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript> (HL = 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione)

[Na(H₂O)₄][EuL₄] · 0.775CH₂Cl₂ (I) has been synthesized by the reaction of Eu(NO₃)₃ · 6H₂O with 1,3-bis(1,3-dimethyl-1H-pyrasol-4-yl)-1,3-propanedione (HL) in the presence of NaOH. Its crystal structure has been solved by X-ray diffraction analysis. Crystals are tetragonal; a = 16.2401(5) Å, c = 11.9113(4) Å, V= 3141.50(17) ų, ρ_calcd = 1.427 g/cm³, μ(MoK _α) = 1.140 mm^?1, space group P4/n, Z = 2. The structural units forming a crystal of compound I are [EuL₄]^? complex anions, [Na(H₂O)₄]⁺ cations, and CH₂Cl₂ molecules. The coordination polyhedron of the Eu atom is an Archimedean antiprism formed by the O atoms of four bidentate chelate ligands L^?.     

X-ray and vibrational spectra on metal complexes with indolecarboxylic acids: Part IV. Catena-poly[{aqua(η2-indole-3-carboxylato-O,O′)zinc}-μ-indole-3-carboxylato-O:O′]

The new zinc(II) coordination polymer catena-poly[{aqua(η²-indole-3-carboxylato-O,O′)zinc}-μ-indole-3-carboxylato-O:O′], [Zn(I3CA)₂(H₂O)]_n [Zn(I3CA)₂(H₂O)]_n has been synthesized and characterized using infrared and Raman spectroscopy and X-ray single-crystal diffraction analysis. The crystals are monoclinic, space group Cc, with a = 33.319(7), b = 5.985(1), c = 8.291(2) Å, V = 1653.1(6) Å³ and z = 4. Each zinc centre is five-coordinated by the bidentate chelating indole-3-carboxylato, one oxygen atom bridging indole-3-carboxylato, water molecule and one oxygen atom bridging indole-3-carboxylato from an adjacent [Zn(I3CA)₂(H₂O)] unit. The Zn–O distances of 1.978(4), 1.987(3), 1.977(4), 1.983(3) and 2.519(4) Å, are typical for distances of such complexes. The infrared and Raman spectroscopic data of [Zn(I3CA)₂(H₂O)]_n in the solid state are supported by X-ray analysis. The theoretical wavenumbers, infrared intensities and Raman scattering activities have been calculated by the density functional methods (B3LYP and mPW1PW) with the D95V^**/LanL2DZ and 6-311++G(d,p)/LanL2DZ basis sets. The theoretical wavenumbers, infrared intensities and Raman scattering activities show a good agreement with experimental. Detailed band assignment has been made on the basis of the calculated potential energy distribution (PED). The results provide information on the strength of zinc-ligand bonding in complex.     

Syntheses and structural determination of the nine-coordinate rare earth metal complexes: [TbIII(Eg3a)(H2O)2] · 4.5H2O and K[TbIII(Edta)(H2O)3] · 5H2O

Two title complexes, [Tb^III(Eg3a)(H₂O)₂] · 4.5H₂O (I) (H₃Eg3a = 3-carboxymethyl-6, 9-dioxa-3,12-diazatetradecanedioic acid) and K[Tb^III(Edta)(H₂O)₃] · 5H₂O(II) (H₄Edta = ethylenediamine-N,N,N′,N′-tetraaceti acid), were prepared and characterized by FT-IR, elemental analyses, TGA-DTA-DTG, and single-crystal X-ray diffraction technique. For I, the Tb³⁺ ion is nine-coordinated by an Eg3a ligand and two coordination water molecules, yielding a monocapped square-antiprismatic (MCSAP) conformation. Complex I crystallizes in the monoclinic system with P2₁/c space group. The crystal data are as follows: a = 9.237(3), b = 10.018(3), c = 23.580(7) Å, β = 99.021(5)°, V = 2155.2(11) ų, Z = 4, ρ = 1.822 Mg m^?3, μ = 3.353 mm^?1, F(000) = 1180, R ₁ = 0.0445 and wR ₂ = 0.1034 for 4262 observed reflections with I ≥ 2σ(I). For II, the Tb³⁺ ion is nine-coordinated by an Edta ligand and three coordinate water molecules also yielding a MCSAP conformation. Complex II crystallizes in the orthorhombic system with Fdd2 space group. The crystal data are as follows: a = 19.373(5), b = 35.429(10), c = 12.114(3) Å, V = 8315(4) ų, Z = 16, ρ = 2.014 Mg m^?3, μ = 2.014 mm^?1, F(000) = 5024, R ₁ = 0.0224 and wR ₂ = 0.0557 for 3189 observed reflections with I ≥ 2σ(I). The potassium cations bridge the coordination spheres yielding many infinite long 1-D zigzag-type chains. The molecular structure of I is more stable than that of II. According to thermal analyses, the collapsing temperatures of crystal structure are 314°C for I and 348°C for II, which indicates that the crystal structure of II is more stable.     

Vibrational spectra and reinvestigation of the crystal structure of a polymeric copper(II)-orotate complex, [Cu(μ-HOr)(H2O)2]n: The performance of new DFT methods, M06 and M05-2X, in theoretical studies

The crystal and molecular structure of a polymeric Cu(II)-orotate complex, [Cu(μ-HOr)(H₂O)₂]_n, has been reinvestigated by single crystal X-ray diffraction. It is shown that several synergistic interactions: two axial Cu-O interactions; intramolecular and intermolecular hydrogen bonds; and π-π stacking between the uracil rings contribute to the stability of the crystal structure. The Raman and FT-IR spectra of the title complex are reported for the first time. Comprehensive theoretical studies have been performed by using three unrestricted DFT methods: B3LYP; and the recently developed M06, and M05-2X density functionals. Clear-cut assignments of all the bands in the vibrational spectra have been made on the basis of the calculated potential energy distribution, PED. The very strong Raman band at 1219 cm⁻¹ is diagnostic for the N1-deprotonation of the uracil ring and formation of the copper-nitrogen bond, in this complex. The Cu-O (carboxylate) stretching vibration is observed at 287 cm⁻¹ in the IR spectrum, while the Cu-N (U ring) stretching vibration is assigned to the strong Raman band at 263 cm⁻¹. The molecular structure and vibrational spectra (frequencies and intensities) calculated by the M06 functional method are very similar to the results obtained by the B3LYP method, but M06 performs better than B3LYP in calculations of the geometrical parameters and vibrational frequencies of the interligand O-H?O hydrogen bonding. Unfortunately, the M05-2X method seriously overestimates the strength of interligand hydrogen bond.     

Syntheses and structures of nine-coordinate K3[DyIII(nta)2(H2O)]·5H2O and eight-coordinate (NH4)3[DyIII(nta)2] complexes

K₃[Dy^III(nta)₂(H₂O)]·5H₂O and (NH₄)₃[Dy^III(nta)₂] have been synthesized in aqueous solution and characterized by IR, elemental analysis and single-crystal X-ray diffraction techniques. In K₃[Dy^III(nta)₂(H₂O)]·5H₂O the Dy^III ion is nine coordinated yielding a tricapped trigonal prismatic conformation, and its crystal belongs to monoclinic system and C2/c space group. The crystal data are as follows: a = 15.373(5) Å, b = 12.896(4) Å, c = 26.202(9) Å; β = 96.122(5)°, V = 5165(3) ų, Z = 8, D _c = 1.965 g·cm^?3, μ = 3.458 mm^?1, F(000) = 3016, R ₁ = 0.0452 and wR ₂ = 0.1025 for 4550 observed reflections with I ≥ 2σ(I). In (NH₄)₃[Dy^III(nta)₂] the Dy^III ion is eight coordinated yielding a usual dicapped trigonal anti-prismatic conformation, and its crystal belongs to monoclinic system and C2/c space group. The crystal data are as follows: a = 13.736(3) Å, b = 7.9389(16) Å, c = 18.781(4) Å; β = 104.099(3)°, V = 1986.3(7) ų, Z = 2, D _c = 1.983 g·cm^?3, μ = 3.834 mm^?1, F(000) = 1172, R ₁ = 0.0208 and wR ₂ = 0.0500 for 2022 observed reflections with I ≥ 2σ(I). The results indicate that the difference in counter ion also influences coordination numbers and structures of rare earth metal complexes with aminopolycarboxylic acid ligands.